Root Locus Asymptotes

When sketching a root locus of a simple closed loop negative feedback system (with positive gain K).... if you have more poles than zeros, we know that they will tend towards infinity along some asymptotes. How do you know which pole will travel along which asymptote?

For example in the system where we have a simple unity gain feedback loop, and G(s) = (s-3)/[s^2(s+10)]

I have attached the MATLAB plot for the system. I was able to draw basically the whole thing, except for which pole goes along which asymptote.